Tuning device for wireless telegraphy.



PATENTED JAN. 27, 1903.

' W. S. HOGG.

TUNING DEVICE FOR WIRELESS TELEGRAPHY.

APPLICATION FILED MAR. 4, 1902.

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al'fo'zmugo PATENTED JAN. 27, 1903.

W. S. HOGG. TUNING DEVICE FOR WIRELESS TELEGRAPHY.

APPLICATION FILED MAR. 4, 1902.

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30 MODEL.

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WILLIAM s. nose, on THE UNITED STATES NAVY, ASSIGNOR F ONE-HALF 'ro THE-GREATER NEW YORK SECURITY COMPANY, OF NEW YORK, N. Y.,

A CORPORATION OF NEW YORK.

TUNING DEVICE FOR WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 719,006, dated January 27, 1903. Application Bled larch 4,1902- Berlal No. 96,676. (No model.)

To all whom it may concern:

Be it known that I,WILLIAM S. HOGG, neutenant-commander, United States Navy, residing at WVashington, in the District of Columbia, have'invented ce rtain new and useful Improvements in Condensers for Electric Circuits; and I do hereby declare the'following to be a ful],clear,and exact description of the invention, such as will enable others skilled in [O the art to which it appertains to make and use the same.

My present invention relates to improvements in wireless telegraph being a tuning device used in any wireless-telegraph circuitpor circuits, in which is Ordinarily contained a condenser and self-induction coils. The device is used to accomplish tuning by varying the capacity and self-induction of any circuit or circuits, according to the formula T 2 1: ME,

0,. the capacity, and L, the self-iuduction, being made so large that T, the period of os- 2 5 cillation, is also large, and only like instruments with alike large period will respond sympathetically. To attain this attuuin g, one or more stations must have like devices in every respect, with indices that throw the relative self-induction and capacity at the same marks on like arbitrary scales, all other parts of the wireless-telegraph system being exactly similar. Myinvention com prises, among other'parts, an outer metal spiral surface,preferably fixed, and an inner metal spiral or continuous sur' face movabbaxiallywithin the outer surface and separated therefrom by a proper dielectric. The capacity can be varied by moving 40 the inner surface longitudinally within the outer and the' self-induction varied by shortcircuiting adjacent convolutions of the outer spiral by plugs OI'Y-B sliding contact. The inner surface can be a spiral, a continuous metal tube or rod, a'metal tube containing iron filings, or bundle of iron wires wound with insulated wire;

My invention further comprises the combination and arrangements of parts hereinafter more particularly described, claimed, and shown in-t'he accompanying drawings, in which- Figure 1 represents in central vertical section, with parts in elevation, a form of condenser embodying my invention. Fig. 2 represents a section taken along the line 2 2, Fig. 1, and looking in the direction of the arrow. Fig. 3 represents a portion of the outer spiral in side elevation. Fig, 4 represents a section taken along the line 4 4, Fig. 1, and looking in the direction of the arrow; and Fig. 5 is a diagrammatic view of the working of the apparatus in wireless telegraphy.

Y Similarletters refer to similar parts throughout the several views.

The device, shown in the drawings comprises, among other parts, a metal spiral shell o open at both ends and conveniently formed by taking a drawn brass or other metal tube and marking out on its surface a spiral of' a desired pitch'fourinches, for example-and then cutting the tube from a point about an inch from one end to the other along the spiral'line. This tube a-is then slipped over a tube.b, of glass, hard-rubber, or other suitable dielectric, which extends at both ends beyond the tube a. I may, however, use oil or even air as a dielectric; but glass or hard rubber is preferred. Within this tube 1) is adapted to slide a metal tube a, closed atone end and either cut in a spiral, as shown,or continuous. If spiral, the spirals of this tubeare preferably of a pitch of one inch-that is, in case the spirals of the outer tube a. are of a four-inch pitch.

Into the closed end of the tube 0 I tap a rod d, which extends beyond the end of the tube 1) and in the case shown is bent at right angles to form an index d forastationary scale e. This rod (1 at the same time forms a support for the end of the inner tube cand is for this purpose mounted in a bracket or stand f, adapted to slide in a guide or way g, and in case this stand is metal the said rod d is insulated therefrom, as by the bushing of in- 5 sulation h. The standfmay be clamped in the desired position by the set-screw 'i. I p The device may be mounted in any suitable insulating-support, such as the support j, and these, together with the guide 9 and support 70 for the scale, may be mounted on any suitable base Z.

The scale 0 is graduated from 34 to 1, corresponding to the convolutions of the in- IOO nor tube 0, so that when the said tube'is all the'way in the outer tube a the indexwill pointto 34,- and when the said tube is pulled out until only one turn of the spiral-is within the outer tube the index will point to 1. The figures on the scale, therefore, in-

dicate therelative capacity. I For the purpose of varying the selfnduction or the "condenser-circuit I provide the outer spiral tube a with aseries of plug holes a one between each pair of adjacent lurns of the spiral. By inserting metal plugs in these holes any number of turns of the spiral may be cutout and the self-induction varied '5. turns are'short-circuited, as above explained,

the self-induction of the circuit may beindiaccordingly. When none of the outer spiral cated L, there being eight turns of said coil. 'lfone plugis inserted and leaves one coil cut but, the self-induction will be relatively L", ,and so on, theself-induction varying with the number of turns out out. confine my invention to this specific graduation.as any arbitrary figures may be assumed. 5.

I do not, however,

The device maybe provided with any suit- "able terminals. In the drawings I have rep-- ,1 f'esented the terminals m m by wires soldered .to the first turn ofihe' outer casing aandthe' lasttu'rn, respectively. There are also termi- ,nals on the ends of the inner spirals n and n.

v f; Figs. 1 and 5 show two of the many ways of using the device.

In Fig. 5 thecombined sending and receiving wire is attached to the terminal 'n audit is led to ground by the circuits, one of which is through the coherer '0. In sending the throw-over switch t' cuts out the circuit through the coherer, and in receiving the circuit is cut out excepting through thecoherer. O in all the figures is an inductorium or source of high tension electricity. I claim as my invention- 1. A tn ning device for electric circuits, havsurfaces or coils; with an intervening dielec-' trio, of combined means-for varying the mutual induction between said coils and at the same time varying thecapacity of the system, substantially as described. r

4. A tuning device, consisting of a spiral metal surface forming one coating of a Leyden jar, a spiral metal surface concentric with the first-mentioned surface andc'apable of movement relative thereto, forming th'eother .coating, a dielectric separating the two coatiugs, means for short-circuiting the outer spi-' ral and, thus varying the self-induction of a circuit, and indices for indicating the relative amount of such capacity and self-induction. 5. A tuning device, consisting of tllQfOF lowing: a spiral metal shell forming one coat ing of a Leyden jar, a metal shell or rod con- I centric with the first-mentioned shell, capahle of movement relative thereto and forming.

the other coating, a dielectric separating the two shells, means for short-circuiting one or more turns of the outer spiraland thus vary-- ingthe self-induction of a circuit, and indices for indicating the relative amount of such capacity and self-induction.

In testimony whereof I aflix my signature v in presence of two witnesses.

- Witnesses:

J. STEPHEN GIUSTA, CLARENCE A. BAT EMAN. 

